The study will assess the diagnosis of Cow's milk protein allergy (CMPA) among infant and children in Assiut University Children Hospital using skin prick test and specific serum IgE

Food allergy is a reproducible specific immune response to the exposure to a given food. Cow's milk protein allergy (CMPA) is a clinically abnormal reaction to cow's milk protein (CMP) via immune mechanisms triggered by milk protein (Boyce etal., 2010) .

According to the European Academy for Allergy and Clinical Immunology (EAACI) and the World Allergy Organization (WAO), a hypersensitivity reaction to cow's milk involving the immune system can be called as CMPA.There is difference between CMPA and non-allergic cow's milk intolerance (e.glactose intolerance) which occurs as a result of lactase deficiency without involvement of the immune system (Venter etal ., 2013) .

CMPA is categorized into immunoglobulin IgE mediated, non-IgE mediated, or mixed CMPA(Sichereretal ., 2001) .

1.9% to 4.9% prevalence of CMPA among children with a peak in prevalence (2-3%) in the first year of life and prevalence of <1% in children aged ≥6 years(Koletzkoetal ., 2012) .

Inclusion Criteria:

1. age : from first day of life - 2 years
2. exclusively breast feeding,breast-fed infants with supplementary foods and non-breast-fed infants with supplementary foods who complain from either frequentregurgitation,vomiting,diarrhea,constipation)with/without perianal rash),bloodin stool or pallor.

Exclusion Criteria:

• Infant and child with gastrointestinal symptoms due to specific aetiology .